/**
 * This is code is released under the
 * Apache License Version 2.0 http://www.apache.org/licenses/.
 *
 * (c) Daniel Lemire, http://lemire.me/en/
 */

/**
 * Interface describing a standard CODEC to compress integers. This is a
 * variation on the IntegerCODEC interface meant to be used for random access
 * and with integrated differential coding
 * (i.e., given a large array, you can segment it and decode just the subarray you need).
 * 
 * The main differences are that we must specify the number of integers we wish to
 * decode as well as the initial value (for differential coding). This information 
 * might be stored elsewhere.
 * 
 * 
 * @author Daniel Lemire
 * 
 */
namespace CSharpFastPFOR.Differential
{
    public interface SkippableIntegratedIntegerCODEC
    {
        /**
         * Compress data from an array to another array.
         * 
         * Both inpos and outpos are modified to represent how much data was read
         * and written to if 12 ints (inlength = 12) are compressed to 3 ints, then
         * inpos will be incremented by 12 while outpos will be incremented by 3 we
         * use IntWrapper to pass the values by reference.
         * 
         * @param in
         *            input array
         * @param inpos
         *            location in the input array
         * @param inlength
         *            how many integers to compress
         * @param out
         *            output array
         * @param outpos
         *            where to write in the output array
         * @param initvalue initial value for the purpose of differential coding, the value is automatically updated 
         */
        void headlessCompress(int[] @in, IntWrapper inpos, int inlength, int[] @out, IntWrapper outpos, IntWrapper initvalue);

        /**
         * Uncompress data from an array to another array.
         * 
         * Both inpos and outpos parameters are modified to indicate new positions
         * after read/write.
         * 
         * @param in
         *            array containing data in compressed form
         * @param inpos
         *            where to start reading in the array
         * @param inlength
         *            length of the compressed data (ignored by some schemes)
         * @param out
         *            array where to write the compressed output
         * @param outpos
         *            where to write the compressed output in out
         * @param num
         *            number of integers we want to decode, the actual number of integers decoded can be less
         * @param initvalue initial value for the purpose of differential coding, the value is automatically updated 
         */
        void headlessUncompress(int[] @in, IntWrapper inpos, int inlength, int[] @out, IntWrapper outpos, int num, IntWrapper initvalue);
    }
}